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    <div align="right">Last update : July 2000</div>
    <p>
      <b>covar</b> -   covariance of two variables</p>
    <h3>
      <font color="blue">Calling Sequence</font>
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    <dl>
      <dd>
        <tt>s=covar(x,y,fre)   </tt>
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      <font color="blue">Parameters</font>
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      <li>
        <tt>
          <b>x</b>
        </tt>: real or complex vector</li>
      <li>
        <tt>
          <b>y</b>
        </tt>: real or complex vector</li>
      <li>
        <tt>
          <b>fre</b>
        </tt>: matrix of type length(x) x length(y)</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
      <tt>
        <b>covar(x,y,fre)</b>
      </tt>  computes the covariance of two variables x and y.
    fre is a matrix of dimensions  length(x) x length(y). In fre the element
    of indices (i,j) corresponds to the value or number or frequences of
    x_i&amp;y_j.</p>
    <h3>
      <font color="blue">References</font>
    </h3>
    <dl>
      <p>
    Wonacott, T.H. &amp; Wonacott, R.J.; Introductory Statistics, J.Wiley &amp; Sons, 1990.</p>
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      <font color="blue">Examples</font>
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    <pre>

x=[10 20 30 40]
y=[10 20 30 40]
fre=[.20 .04 .01  0;
     .10 .36 .09  0;
       0 .05 .10  0;
       0   0   0 .05]
s=covar(x,y,fre)
 
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    <h3>
      <font color="blue">Author</font>
    </h3>
    <p> Carlos Klimann</p>
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